Problem Statement

Numbers are far easier to spell in Esperanto than in English. Numbers 1 through 10 are spelled as follows: "unu", "du", "tri", "kvar", "kvin", "ses", "sep", "ok", "nau", "dek". Numbers 11 through 19 are spelled: "dek unu", "dek du", ..., "dek nau" - a "dek" followed by a single space and the number for the last digit. Numbers 20 through 29 are spelled: "dudek", "dudek unu", "dudek du", ..., "dudek nau". Similarly, 30 is "tridek", ..., 90 is "naudek" - we just join together the number of tens and "dek". There are no exceptions like "twelve" or "thirty" in English.

Given an int x between 1 and 99, inclusive, return its Esperanto spelling.